The O-ring, code 106977, is a precision sealing element used in the MAN L21/31 engine to prevent leakage between stationary or moving components operating under pressure. Its circular elastic design allows it to create a highly effective seal by adapting to dimensional variations caused by temperature changes, vibration, and mechanical loading. Commonly installed in lubrication, cooling, fuel, and hydraulic systems, the O-ring helps maintain system tightness while protecting internal engine components from contamination. Manufactured from high-quality elastomer materials with excellent resistance to heat, wear, and chemical exposure, the O-ring contributes to improved operational reliability, reduced maintenance intervals, and extended service life of the engin